Analogue computer



3 Sheets-Sheet l om ZOtuwwr .C. H. HOEPPNER ANALOGUE COMPUTER May ll, 1954 Filed Feb. 21, 1950 3 Sheets-Sheet 2 Filed Feb. 21, 1950 n D u u u n n nn .n n u .u

a s c CoA/640 Hamm/El? N @ARN 3 Sheets-Sheet 3 COMP/90 H. /OEPPNE AT? 1? Ty C. H. HOEPPN ER ANALOGUE COMPUTER May 1l, 1954 FiledFeb. 21, 1950 Patented May 11, 1954 ANALOGUE CORTPUTER Conrad H. Hoeppner, Waltham, Mass., assignor to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application February 21, 1950, Serial No. 145,478

11 Claims. 'i (Cl. 332-9) This inventionrelates to analogue computers, and more particularly to a type of analogue computer useful for computing linear data from data containing known non-linearities.

In telemetering intelligence devices, the signal in nearly all cases is to some extent non-linear. These non-linearities may be due to the measuring device or the signal transmission system with the result that information read or recorded directly from a telemetering system must be corrected by means of calibration curves before it is presented in useable form. To date, this calibration work has been done by manual labor by comparing the recorded data with a calibration curve and then again recording or plotting the corrected data. Such a procedure is slow and costly, particularly where there are many thousands of separate pieces of information to be so corrected.

This invention discloses an apparatus which automatically compares incoming data with a calibration curve and corrects said data prior to the initial recording thereof. This eliminates' the correction and replotting of the data by hand. One means for producing the calibration curve comprises a function synthesizer which continuously generates a wave form, conforming to the calibration curve, against which the incoming data is compared. The function synthesizer comprises a time delay line having its input connected to a source of pulses. At spaced intervals along said delay line are connected the inputs to a plurality of cathode follower amplifiers such that, when a pulse is introduced into one end of the delay line, it travels down the line and successively pulses the inputs of each of the cathode followers. The cathode load of each of the cathode followers `comprises an adjustable potentiometer, the variable taps of which are connected to a common output signal channel. Thus, it may be seen that, when a pulse travels along the delay line successively triggering they cathode followers, successive pulses are introduced into the output channel, the magnitude of which is dependent upon the settings of the variable taps of the potentiometers. Since the time delay interval between adjacent cathode followers is made substantially equal to the length of the pulse traveling down the delay line, the signal output to the common output channel will be a substantially continuous wave whose amplitude varies successively in accordance with the settings of the cathode followers of the potentiometers. By adjusting said potentiometers, a good approximation of any desired output wave form may be synthesized. Y'

This synthesized wave form may be compared with an incoming signal for correction therewith in any one of several ways. In a system used for correcting intelligence being transmitted by pulse position modulation, there may be used, for example, a synchronizing pulse whose cyclical position remains fixed, and an intelligence pulse whose time position varies relative to the synchronizing pulse. The synchronizing pulse may be used to initiate a pulse forming circuit which starts a pulse down the function synthesizer delay line. The synchronizing pulse may also be used to initiate the start of a saw-tooth generator. The output of the function synthesizer is then mixed with the output of the saw-tooth generator to form a modified saw-tooth wave which is applied at the deflection plates of a cathode ray tube. The intelligence pulse is applied to the control grid of the cathode ray tube in the form of a positive pip such that the cathode ray tube has a spot thereon when the intelligence pip is applied to the control grid, but during the remainder of the time is blank. It may be seen that the intelligence pip will arrive after the initiation of the saw-tooth sweep, and the bright spot will appear at some position lying in a line perpendicular to the deiiectionI plates of the tube on the face thereof. In the absence of a signal from the function synthesizer, the position of this spot will vary as a linear function of the difference in time between the synchronizing pulse and the intelligence pulse of the incoming signal. However, by superimposing a wave from the function synthesizer on the saw-tooth sweep wave, the position of the spot on the face of the tubemay be changed by a certain predetermined amount dependent upon the output of the function synthesizer at the particular instant that the intelligence pulse arrives at the control grid of the cathode ray tube. By adjusting the output of each of the cathode follower stages of the function synthesizer, any desired position correction may be applied to the spot on the cathode ray tube at any desired time position of the intelligence pulse relative to the synchronizing pulse. A photograph film may then be placed in proximity with the cathode ray tube and continuously moved relative thereto, thereby producing a continuous record of the position of the spots on the cathode ray tube. The position of these spots having been corrected by the wave generated by the function synthesizer, the information recorded on the nlm will be accurate and linear.

Another species of the device may be used to correct information occurring in the form of form comprising the sawetooth wave.forn'1:hav".v ing the correction wave form generated by the function synthesizer superimposed thereon. This wave form is then compared with the intelligence tooth generator are; mixed to produce arwave signal by a coincidence gatewhich producesca" pulse whenever the intelligence-signal fis equal- Y in amplitude to the calibrating=waveform.: `The output of the coincidence gate is used to termiie. j

nate the generation of a rectangular. pulse fromw. a saw-tooth gate. The initiationof therectangw lar pulse generation by the saw-tooth gatemis governed by a synchronizing pulse from the master oscillator.-l -The result isthat the-,length of the pulse .generated by the `saw-tooth. gate varies as a yfunctionlof the amplitude of. theinput .f signal andi thecorrection .introducedby the func?. tionsynthesizer. The. outputbf the sawftooth.

gate-is-'used toI drive asaw-tooth. generator which.. i

produces `a sawetooth .Waveform whoseamplitude. variesrdirectlywith thelengthof theinput pulse...\. The amplitudeof-thesawetooth wave is measuredv i by a peakriding. .cathode follower, .the .output of whichis appliedwtothe. deflection plates of a cathoderay.tube.` yThe cathode ray beam continuouslystrikes the .screen to form a spotwhose..

positionmovesas .af function ci thecorrected.

signal.y Thus, it. may be seerrthat information,

whichcontains known errorshaving.anon-linear.

relationtto said information,.1nay.be automati.

cally corrected`v during thetransmission thereof Other objectsandadvantages of thisinventionv Willybe .apparenti as fthe.. description .thereof progresses, reference .,being. had'lto the`..accompanying. drawings wherein;

Fig. l illustrates aecirc'uit. diagramA of a Ifun'c- VtionsynthesizerA whichmay. be used inithe .utilization-of thisfinvention; c

Figwzillustrates. a block ,.diag'ramof one Yform of circuit-whichmay be used-.with,thefunction synthesizer of Fig.A .14 to correct pulse .position modulation intelligence;

Fig;` 3v illustrates .a block-diagram of a. secondcircuit .which .maybe used to. correct continuous wave .informatiomr and Fig, 4.illustrates.a recording. of, a lcorrected intelligence eignal..which.-may be produced on av iilm..by the .device .shown in Fig. `2 .V l l Reierringnow. to Fig.` 1, whichillustrates theA function syfnthesizenthere is shown a pulse .in-

putrIIi whichmayba for example, a coaxial cable' l. in orderto preserve the sharpness of thelpulse during. transmission. from the pulse generation'.

device to theinput. The pulse input. It is' con-. nected to aldelay` line network II having aplurality.- of sections. .Each sectionlcoznprises a cenL ter .tapped chokeiZ connected in series with the.4v input III and the input to the next section. The

center. tap of. the choke i2 is.' connected through.

a condenser. I3 to.. ground and therebyto the .out-- side .shieldrof the coaxial input .,I. .Each section producesa timedelay of, for example,.one microsecondsuch that, iftwentyisections, for example, asrshownf here, are-usedf the overall delayof the Y. timefdelayrnetwork Ywillbe twenty-microseconds,

each Vsection .-beingj 4identicall with 1the `irstedescribed section and having, respectively, a choke Y l2 anda-condenserfl. *Eachof thef'junctions' betweerrthe chokes I2: isiconnected, respectively,y

The plates i8 of the cathode followers I'I are all connected to a common voltage bus I9 which is connected to the cathode 2i) of a voltage stabilizingrtubeizl. rCathode-2B isconnected to groundsthrough :a bleeder resistor 22 in parallel with a lter condenser 23. The plate 2d of tube 2i' is connected directly to a source of positive direct potential of, for example, Sll volts. The grid'25 f tube 2i is connected to a junction betweentworesistors'vZI and 26a, the other end of resistor 2a'being.Av connected to ground, and 'thetother/:end .of resistor 26 being connected to plate 24. Thus,.it may. be seen that, due to the cathode follower action", the potential of cathode 20 andgftherefora the potential of all of the plates I8 will remain at substantially the'potential of grid .25. Rapidfuctuations in the ground and bus .L9 will `be abscrbedby lterl condenser. 23, lthereby preventingthefeeding' of pulses into.

the high voltage supply.

Eachzof thel cathodesl'i of cathode `followers- I'I is connectecbto oneend oa separatefvariable.' Ypotentioncieter-28, the other `ends of said .poten-VV tiometer..beng cennectedto ground/Each variable tap 29A of` eachpotentiometer A2S, .which may` Y be of the helipot-.typa is. connected through a separate-crystal rectier. ,3Q to one `of a.' pair of common. grids of. acathodefollower pulse mixer stage 3,2.

The grid bias voltage for gridsl is'. supplied as follows. .A voltagedividennetworkvcomprisingtwenty-one resistors Iainiseries isconnectedV betweena-negative voltage sourceof, for example, 150v volts. and'zground... TheV 'junctions between delay; line. Il andbecomes., slightly .attenuated thereby; the gains'lof the sections increase to substantially. compensate .for the attenuation so thatall the sections -of thesynthesizer will pro,-

ducesubstantially equal outputs forV similar settings of potentiometers ,23. l Y

As shownhere,..the. outputs of the helipots vof sectionsonethroughten are. connected to a commonlgrid 3 I. of. one. section ofthe cathode fol-"1.

lower-.stage 32, while .the outputs of sections eleven through-twenty are .connectedto another grid 33 of a secondsectionof cathode follower stage. 32.

Thecathodes Meand ofbothsections of stage 32 are connected together. and .to ground throughI a cathode-loadresistor 36 across which the youtputsignal srdeveloped .-andfed, for example, by a coaxial cable to autilization circuit `to be de.V scribed-rfpresentlyf.The platesv 31 and-3-5 of both sections-:arefconnectedtogether zand to a source of positivefpotential; The grids .3| and 33 are connectedto ground through-grid load resistors 3% and 49, respectively Thefuseof crystals 30 in the .outputsfbetween taps` 29 andthe commonA output stage-'32,preventsipulses-,from one seci tionwof thedelay line `network from feeding through the'common connectionl at grid-3l or grid.3 3 to otherfstagesnoftheysystem.l` After a,

pulserhasetraveied down -the-delayline- I I, it is 'of the circuit to be described-presently Referring now to Fig. 2, there is shown an overall functional block diagram illustrating one method of use of the function synthesizer of Fig. 1. A pulse position modulation signal having intelligence to which a correction is to be applied is fed into a channel separator 42. Each signal cycle comprises two pulses, an initial or, synchronizing pulse 43 and an intelligence pulse 44 which lags behind synchronizing pulse 43 by an amount which varies as a function of the intelligence being transmitted by the signal. Channel separator 42 comprises a circuit which separates the synchronizing pulses 43 from the intelligence pulses 44 and may be of any desired type as, for example, that used in the television art. The synchronizing pulses are fed from channel separator 42 through an amplifier stage 45 to a gas triggered tube 48 which discharges a pulse forming line 46cI to produce a rectangular'pulse having a duration of substantially one microsecond. The pulse generated by gas triggered tube 46 is fed to the function synthesizer II lthrough input I and travels down the delay line thereof producing an output wave at the cathode follower mixer stage 32 which has a predetermined shape dependent upon the settings of the potentiometers 28. n

After passing down the delay line of the function synthesizer I I, the one microsecond pulse is fed through a second delay line 41 having a delay which may be, for example, three and onehalf microseconds, to a saw-tooth generator gate 48. Saw-tooth generator gate 48 may be, for example, a flip-flop multivibrator having two inputs. One input is connected to the output of Ithe channel separator 42 which feeds the synchronizing pulses to amplifier 45. Each synchronizing pulse triggers the saw-tooth generator gate 48 initiating the 'generation of a pulse output therefrom. The pulse from delay line 41 is connected to the other" inputV of the saw-tooth generator gate 48 and terminates the pulse whose generation was initiated by the pulse from the channel separator 42. The output of the sawtooth generator gate 48, therefore, is a rectangular pulse having a duration on the order of twenty-five microseconds. V

'I'he output ofthe saw-tooth generator gate 48 is fed to a saw-tooth generator 49 which produces a `saw-tooth wave form of the same duration as the rectangular pulses. This saw-tooth generator `may be any of the well-known types which producev a linear `triangular wave. The output of saw-tooth generator 49 is fed to a nal mixer I).l The output of cathode follower 32 is also fed through a switch 5I to iinal mixer 58 whereit is added to, and thereby superimposed upon, the triangular wave form produced by sawtooth generator 49. Switch 5I allows optional connection of an inverter stage 52 into the circuit between the cathode follower and the final mixer 50. Thus, if desired, the wave form generated by the function synthesizer I l may be inverted before being mixed with the saw-tooth wave form. The output of the final mixer 58 is fed to a lter 53 which rounds off any sharp discontinuities which may exist in the wave produced by the function synthesizer. The output of lter 53 is fed through an amplifier 54 and a cathode follower 55 to the deiiection plates 5B of a cathode ray` tube 51. As shown here, the cathode follower 55 feeds the horizontal deflection plates of the tube 51 such that all positions of theelectron beamlstriking the screen of the tube 51 iwill lie in al horizontal line. The intelligence pulses 44 are fed from channel separator 42v to the control grid 58 of tube 51 appearing thereon. in the form of positive pips. With t-he control grid 58 adjusted to below cutoff, the appearance of positive pips on the grid will allow electrons to flow to the screen of tube 51 producing a spot thereon. The position of the spot appearing on the screen of tube 51 will be determined by the particular time at which the intelligence pips 44 brighten the screen with respect to the particular phase relation of the wave form produced at the output of the final mixer 50.

In the absence of a correcting wave from the function synthesizer II, the position of the spot on the screen of tube 51 will vary linearly across the face thereof as a function of the position of the pulse 44 relative to synchronizing pulse 43. By varying the linearity of the saw-tooth Wave form applied to deflection plates 55, the position of the spot on the screen of tube 51 may be adjusted relative to the position of intelligence pulse 44 with respect to synchronizing pulse 43.

This variation is accomplished by adjusting the'4 potentiometers of the cathode followers I1 in the function synthesizer I I which is being' energized by the pulse from gas trigger stage 46 at the same time that intelligence pulse 44 is being applied to control grid 58.

Thus, it may be seen that, for twenty time positions of pulse 44 with respect to synchronizing pulse 43, the physical position of the spot on the screen of tube 51 may be adjusted horizontally across the face of the scope. Due to the action of lter network 53, positions between these twenty adjustment positions will tend to: be interpolated toward their correct value-s. Thus. when the intelligence being carried by the input signal is for any reason a non-linear function of the relative position of synchronizing pulse 43 and intelligence pulse 44, and that non-linearity can be determined, for example, by Calibrating measurements, a correcting wave may be produced by suitable adjustment of the potentiometers 28 of function synthesizer II such that the position of the spot on the cathode ray tube 51 will vary as a linear function of the intelligence.

In order to continuously record this corrected intelligence, there is provided a photograph film 5S supported on two reels `(il) and 5I, respectively. Reel 8l has continuous uniform rotary motion imparted thereto by means of a motor `b2 such that the film 59 is drawn past the face of tube 51 in a direction perpendicular to thedeiieotion` line of the electron beam at a uniform rate. Once every cycle of the incoming wave, a spot is produced on the screen of tube 51' and recordedl by film 59, the transverse position of said. spot on said film being a measure of the intelligence.

For example, if a sinusoidal wave form is being transmitted by the system, the relative position of pulses y43 and 44 will vary substantially sinusoidal. However, variations from the sinusoidal pattern will occur due to non-linearities in the transmitting system. These non-linearities will be corrected due to the action of the function synthesizer II with the result that the position of the spot on tube 51 will vary across the face of the scope as a sinusoidal function of time. The result will be a locus of spots recorded on' the film 59 which lie on a true sine wave.

In Fig. 4, there is shown a section of lrn 59 illustrating such. a sine wave. As shown here, during each cycle of the sine wave, there are twelve cycles of the intelligence pulses 54, thereby producing twelve spots on the screen of tube 51.

Y which sharpensv the .rise of the sine Wave.

output 'of peaking amplifier 63biisfed to a. block ing'oscillator.63cfvvhich may be, for' example, a

justed'. for frthe'- particular system to compensate fora-ll of thefnon-line'arities therein, anyform'of -f Wavre maybe transmitted over'said system and be recorded? in its corrected form;

Whileaparticular design 'of the system .used-f. at 'presentthas an input pulse: frequencyV signal of approximately"-1409-=cycles per second,y higher frequencies could be used: Forexample;since a complete-f correcting f cycle L takes approximately twentyfive microseconds; the signal pulses could arrive at the/rate of approximately 40,() cycles per;. second .without-jamming the correcting sysf` temp". In addition; for vstill higherfrequencies. thehfunctionvsynthesizercould-be built with less delayr per section, thereby decreasing-the time for eachcorrectioncycle, and, as a result, increasing thewmaximum allowablefinput pulse repetition:

freduencyfy Turning new -to Fig.-3, therefis shown'a'system utilizing' a function synthesizer for correcting data'lappearing as a continuouswave signal whichvaries in amplitude. In this system,athe

incoming'signal 'isfsampled or rneasuredarmrox imately 1400 times per second and a correction introduced theretoat each measurement.V The sampling-rateis governed by a master oscillator BSwWhiCh-'may be of anyWell-known stable type.

The 'output-is fedat'o a peaking amplifier tb Whichmay-be, for example, a standard vacuum tube-amplifier-fhaving. an inductive plate load' The standard -f transformerI coupled vfeedbaclz; oscil- .lator which is highly regenerative.- VVAThe output multivibrator L comprisingrtwo tubes which :prow

duces'a positive pulse in the platecircuitof one tubefancla negative pulse in the plate circuit of the other tube; fboth pulses 'being 'generated simultaneously and having a duration of five microseconds.x:'-Ihe negativev five *microsecondf4 pulse is fedto a. diiferentiator. a which produces a negative vpip followed five microseconds later inating-.the negative input pip andrprodubing' an output waveform which consists essentially o 1 a positive pip.-

The-positive pip vis fed through fa three.l andf oneyhalfmicrosecond delay line 66 and'apulse amplier-.stagel to a gas triggerqtube 46 Which discharges-a `pulse line 65a-, thereby producing a;

one .'microsecond positive pulse .output.- TheV pulse isrfed to fiuiction'synthesizerl l of the 'typev 1.'

shown in Fig.' l, and .travels along'- the delay line cgi) ' producing successive -outputs 'at the potentiometers-of thecathodefollowers.v The outputs of thepotentiometers'offunction synthesizeri I will f feed through-a common cathode follower mixer 32 andia filter network of the lovV-passtype` 59 which eeliminates `.sharp discontinuities in the wavevgenerated by the functionsynthesizer l l.

The positive pipfrom cathode follower'v 65 isv also fed to a saw-,toothA gate 19 which mayfbe a flipJ-flopmultivibrator similar to that of gate 43 described. in Fig. 42. The positive pulse of the 1 cathode-follower 65 initiates the generation of a 8 a functionffsynthesizerzil passesthrough`Y fa" three." andi lone-'fhalfve microsecondii delay: -linem'lfl and .e throughnanv `fampliier :12, and is: thfen-:applied.to` saw-tooth gate-Tit to'terminate-Ythegeneration.of the rectangular'. pulse.:l'=- Y The rectangular pulse 'genei'atedby thesaw 1* tooth gate is fed to a. saw-#tooth generator` .'13 whichgenerates a.' linear-.saw-tooth Waveffornr.-y This Waveform'is fedrtofa-mixer 14. .-'The output.;l of the function -.synthesizenH is also fedto mixer 14 through. cathode follower Y 32, v'filter t9 anda' switch: 'l 5, which 'in one. position allows the signall to'pass Adirectly from-filter88 to mixer ld, andf from the' other position passes .tlifesignalthrough an 'inverter' 1.6, if so fdesired. T'The. foutput; of mixer 'M comprises: the saar-'toothy VWave/form havingthecorrection Wave developed by function synthesizer Il additively'superimposed-thereon similar. to theoutput of mixer; 50 in Fig. 2.v This.` output is fed through-afcathod'e follower-T11 and an ampliiierV 18 to a-coincidence-gatel9- The raw :uncorrected input data 1- signal is also :fed through .an amplifiert to coincidence gate'f'l9.

Coincidence gate -19 comprisesfacircuit .whichff generates a pulse-.When the .input Vfrom:amplifier 'i8 is-substantially. equalto the inputvfromamplier B0. This circuit may be, .for examplefa space discharge device. 'having af-.grid 'platefa-nd Y cathode with vone signalapplied 'to f the cathode, '-.rf and-.the other signal applied `to the-grid;and.-the l output taken'ioff by a. load in ther plate 1circuit.. .7 If, for example,` theV saw-toothWaveapplied-:to coincidence gate -19 is' of constantlyrincreasing-. amplitude, as shown {here-this- Wave'wouldfbe applied tothe gridof the.coincidence.gate:i4 The:- f raw datavinputfrom amplifier- Would-be applied to the cathode. Since .the input from-.am plier. data 8i) applied -to the cathode is .at the beY ginning of each sampling-'cycle'largerfin ampli-1 tude than the saw-tooth Wave from amplifier'l, f thecoincidence gate willbe non-conductive. 'f the saw-tooth. Wave -form-increases in-` amplitude; a point .Willbe reached FWhere thefgrid voltage-fof.A i the coincidence :.gate will/approach l"the cathode f"- Voltage. bringing. the4 tube out of cutoff and: pro.- ducing a voltage output pulse inthe .platecircuiti-w.l

The output of coincidence gate T9 isffedtoan e" amplierdiiferentiator 8| Whichproducesan out-r put pip corresponding to the fleadiin edge Jof the f pulsegenerated by thecoincidencegate 13. f

Theoutput of amplifier differentiator 8l' is ap-f plied to asecondfsaW-tooth gate 82 to terminaterv. a pulse being generated therein; said.pulse.haw-fwv ing its generation initiatedin thefollowing rnari-l ner The positive .pulse output of five microsecond` i gatell is fed througha square. Wave amplifier 83 and a diifrentiator 84 producinga'negative pip.` followed five* microseconds later .by a positive?- pip.' Thepositive pip triggers onthe saw-tooth. gate" 82 which.V may be 'a flip-nop multivibrator similar to the gate l0. Y

Thev relative cyclical position of the pulsefrom' amplifier diilerentiator 8|'` willvary Vwith respect' to the fixed cyclicalposition of, the" pulse'lfronf" N diiferentiator '84 as a function of 'tl'eamplitudeof the input signal'from amplier 80, and, there'` fore, the output'of sawltoothgatei will be a rectangular pulse Whose lengthjvaries as a func:V- tion of the amplitudeof the'input'signal from amplifier'. 'The outputlfromsawdocth gate' 82 isfedto a `saw-tooth`generator'85 Which`pro, Y duces a triangular'wave. The durationof the saw-tooth. Wave lform produced by generator -85 Will vary directly with the lengthrof Vthe=rectangu.....:. lar pulse output. ofz saw-toothgate.v 82. Therefore, rri

the longer the time allowed for thegeneration of the saw-tooth wave, the higher will be the peak amplitude thereof. Thus, it may be seen that the peak amplitude of the saw-tooth wave will vary as a function of the amplitude of the input signal from amplifier 8,0 and the wave output of the function synthesizer l l. In order to insure complete discharge of the saw-tooth generator following each wave to thereby insure a fixed zero level, an output from square wave amplier 83 is fed through a difierentiator 86 to trigger a blocking oscillator 81, which produces a pulse of short duration, for example, one or two microseconds, which is applied through a D. C. restorer 88, which may be, for example, a diode, to saw-tooth generator 85 following the termination of each saw-tooth wave, thereby insuring the return of saw-tooth generator 85 to its zero position prior to the initiation of the generation of the following saw-tooth wave.

The output of saw-tooth generator 85 is fed through a cathode follower 89 having a peak riding circuit in its output. Peak riding circuit comprises a capacitor and resistor in series in the cathode circuit of the cathode follower 89. Across the capacitor and resistor is placed a discharge device which is periodically rendered active to discharge the capacitor in the following manner. An output from square wave amplifier 83 is fed to a recovery gate 90 comprising a delay multivibrator such that the tube across the cathode circuit of cathode follower 89 is made conductive a short time before the initiation of the saw-tooth generator 85, thereby rapidly discharging` the peak riding cathode follower for a very short period, for example, one microsecond. Thus,.it may be seen that, when saw-tooth generator 85 is triggered and generates a saw-tooth Wave, the cathode circuit of the cathode follower 89 will develop a voltage which rises until the saw-tooth generator 85 is shut off and will remain at this level until the start of the next sampling cycle. At this time, a pulse applied to the shunt tube across the cathode circuit from Square wave amplifier 83 and recovery gate 90 will discharge the peak riding circuit, thereby conditioning it for reception of the next amplitude of the saw-tooth Wave. The output of cathode follower 89 is fed to a lter 9| which smoothes over the transients caused by the periodic discharges of the peak riding capacitor by the recovery gate. The output of filter 9| is fed to the horizontal deflection plates 56 of a cathode ray tube 51 similar to that of Fig. 2. Positioned adjacent the screen of cathode ray tube 51 is a film 59 supported on reels motor 62 similar to that of Fig. 2. In this system, the electron beam continuously strikes the screen, and, as the film moves past the face of the screen, a continuous trace is recorded thereon depending upon the position of the spot on the screen of tube 51. It may be seen that the time in the sampling cycle at which the coincidence gate produces a pulse may be adjusted for any particular amplitude of input data by adjusting the cathode potentiometer of the function synthesizer I l producing the output pulse which arrives at the coincidence gate 19 at the particular time required to open the gate. Thus, for a, particuiai amplitude of input signal to amplifier 89, the position of the spot on the screen of tube 51 may be adjusted by adjusting said potentiometer. Each potentiometer, therefore, may be adjusted vto adjust the position of the spot on the screen when that spot falls within the particular area 60 and 6| and driven by a of the cathode ray screen controlled by that potentiometer. For example, the horizontal line on which the spot on the screen of tube 51 will always lie is divided into substantially twenty equal sections, each section being controlled by a potentiometer in the cathode follower circuits of the function synthesizer il. If the input signal varies at a rate of, for example, cycles per second, each cycle will be sampled substantially fourteen times by the correcting system, and, due to the action of lters 69 and 9i, the portions of the signal in between the fourteen sampling positions, will be interpolated and smoothed to approximate the accurate positions.

Thus, it may be seen that this invention discloses a device whereby any information may be converted into electrical signals, and these signais may he corrected or modified in any desired manner by merely adjusting the settings of the function synthesizer it. In actual4 practice, a multiplicity of potenticrneters are provided for each cathode follower of the function synthesizer li, and a gang switch shifts operation from one set of potentiometers to another so that several sets of calibrations may be set up at one time,

and calibration may be shifted from one set to another by means of the switch. Thus, information coming from different sources, for example, a pressure gauge, and then a temperature gauge with each having different non-linearities, may be successively corrected by the system by simply having the calibration curve for the pressure measuring device set up on one set of potentiometers, and the calibration curve for the temperr ature measuring device set up on another set of potentiometers. When it is desired to record pressure information, a switch is set to connect the first set of potentiometers, and, when it is desired to record temperature information, the switch is set to connect the second set of potentiometers. It should be understood that this correcting device is actually an analogue computer which will continuously compute information according to a curve which may represent an exceedingly complex equation.

This completes the description of the particular modifications of the invention illustrated herein. However, many modifications thereof will be apparent to persons .skilled in the art. For example, the function synthesizer Il could be used in other systems besides telemetering systems and could use other' delay means in place of the delay line shown. For example, a line of pulse generating tubes which were successively triggered by pulses from preceding tubes could be used. Therefore, applicant does not wish to be limited to the particular details of the invention illustrated herein except as defined by the appended claims.

What is claimed is:

1. An electron discharge device comprising a plurality of signal translation channels, said channels having different substantially constant signal amplification factors, a source of periodic pulses, and signal delay means for connecting each of said channels to said source, said delay means producing a delay between one of said channels and-said source which differs from the delay between said source and an adjacent channel by substantially the duration of a pulse from said source.

2. An electron discharge device comprising a source of intelligence signals, a source of predetermined signal calibration Waves, and means for modifying said intelligence signals in con- Vforn'iancewith said calibrationiwaves asa nondetermined-phase position of a cycleofipulses of linear function ofthe/intelligence ofsaid intelligence signals.

3. An electron discharge device comprising a f source of intelligence signals, a source of pre said intelligence signals,:and means for-:1 cornparing. said. calibration Waver withf-saidL-intelligence signals comprising alcatlioderayftube determined signal calibration waves, vand means for modifying said intelligence.. signals as apredetermined non-linear'function ofthe intellilgence of saidy signals, said function being determined from said: calibration Waves, and remaining fixed with respect to time.

4. An elec-tronY discharger device comprising a source of intelligence signals, a source of predetermined sig'nal-calibration Waves, and means for modifying said intelligence signals as a pre-y Y determined non-linear function of the intelli- -gence ofl said signals, said function being deter- -mined from said calibration waves.

5. An electron discharge device comprising meansfor receiving pulse positionmodulated intelligence signals, means v for synchronizing the generation ofa calibration Wave with aV predetermined phaseposition of a cycle of pulses ofv-'sa-id Vintelligence signals, and means for comparing said calibration Wave with said intelligence signals.

6.Anelectron ydischarge device comprising `means forreceiving pulse lposition modulated -intelligencesignala means for synchronizing the genera-tion ofacalibration wave with a predeterminephase position oi av cycle of vpulses ci said intelligence signals 'and means for comn paring said calibration wave with said intelligence signals comprising a cathode rayV tube.

7.1An"electron discharge device comprising lmeans for receiving pulse position modulated vk"intelligence signals,-means^for synchronizing the v generation of af calibration `vvave'ivitlfi a predetermined-phase vposition of a' cycle of pulses of Lsaid intelligence signalsyand means forl compar` -ingsaid` calibration -wave with saidl intelligence signals comprising a` cathode ray Atube Whose electron-beamposition-is determined by a signal comprising said calibration wave.

8. An electron-discharge device 'comprising means for-receiving pulse position"V modulated v intelligence signals; f means' f for lsynchronizing the-'generation Yof a calibration Wave with'a pre- Whose electron'beamgposition iscontrolled as avfunction of said calibration;vvaveV and-whose electron beam intensitygis-controlled as a'func- :tion of :said-intelligence signals.

9, An LelectronidischargeA device` comprising means for receiving continuous wave intelligence signals, means for cyclically sampling said-intelligence signals, and means for synchronizingathe c generation of calibration wave with said-cyclical sampling means.

10. An\.felec-tronl discharge device comprising means for receiving continuous :wave intelligence 1 signals,I means-for cyclically measuringsaid y .intelligence signals; meansfor synchronizing-the generation of a calibration Wavewith said cyclical measuring-means, and means for comparing -said calibration 4vwave yWitli Vsaid-'intelligence ry signals.

' 1l.An-\ electron V'discharge device-comprisingV means for receiving-continuous lWave intelligence L signals, a'i'source ofY predetermined-signal calibration vvvavesmeansv for comparing said `calibration waves With-saidintelligence signals `Comprising means iorA'cycl-ically sampling said'intelligence signals;andemeans formodifyingsaid intelligence lsignals in conformance-With saidcaliyeration` Waves asav function of the intelligence of said intelligence signals.

References cited in theme ofV tnis'pant 

